1. Field of the Invention
This invention relates to a light emitting diode (LED) illuminant system, a manufacture method thereof, and a backlight module using the same; more particularly, this invention relates to a light emitting diode illuminant system having high color temperature and a manufacture method thereof.
2. Description of the Prior Art
Display panels and panel display devices using the display panels have become the mainstream of various display devices. For example, various panel displays, home flat televisions, panel monitors of personal computers and laptop computers, and display screens of mobile phones and cameras are products widely using display panels. Particularly, the market demand for liquid crystal display devices largely increases in recent years. In order to meet the function and appearance requirements of liquid crystal displays, the design of backlight modules used in liquid crystal display devices is diverse.
In order to meet the requirements of small size, light weight, and less power consumption, light emitting diodes have been widely used as light sources of the backlight modules. Among all kinds of light emitting diodes, white light emitting diodes (white LEDs) are more often used as the backlight module light source. The white LEDs available in market usually emit white light by exciting white fluorescent powder with a blue light chip. FIG. 1 illustrates a chromaticity distribution diagram of the light emitted from such white LEDs. As illustrated in FIG. 1, the distribution of the light emitted from the white LEDs generally falls between (0.261, 0.222) and (0.268, 0.234) in the CIE chromaticity coordinate. Because the chromaticity range within the white light range is relatively close to the low color temperature area, the white light emitted from the white LEDs has a relative low color temperature.
For a conventional small liquid crystal display, there is no problem of using white lights of low color temperature as the light source of the backlight module. However, for a larger liquid crystal display, particularly for a liquid crystal television panel, due to the high color temperature requirement of the industrial standards, using white lights of low color temperature as the light source of the backlight module is difficult to meet the design standards. For example, the emitted light has to reach (0.2788, 0.292) in the CIE chromaticity coordinate to obtain a color temperature performance of 10,000K. In order to solve the problem, how to increase the color temperature of the light without significantly increasing the cost has become one major issue.